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  <title>计算字符串的 MD5 散列值</title>
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 <body class="docs"><div id="layout">
  <div id="layout-content"><div id="function.md5" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">md5</h1>
  <p class="verinfo">(PHP 4, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">md5</span> &mdash; <span class="dc-title">计算字符串的 MD5 散列值</span></p>

 </div>
 
 <div id="function.md5-refsynopsisdiv">
  
<div class="warning"><strong class="warning">Warning</strong>
 <p class="para">
  It is not recommended to use this function to secure passwords,
  due to the fast nature of this hashing algorithm. See the
  <a href="faq.passwords.html#faq.passwords.fasthash" class="link">Password Hashing FAQ</a>
  for details and best practices.
 </p>
</div>

 </div>
 
 <div class="refsect1 description" id="refsect1-function.md5-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="methodname"><strong>md5</strong></span>
    ( <span class="methodparam"><span class="type">string</span> <code class="parameter">$str</code></span>
   [, <span class="methodparam"><span class="type">bool</span> <code class="parameter">$raw_output</code><span class="initializer"> = <strong><code>FALSE</code></strong></span></span>
  ] ) : <span class="type">string</span></div>

  <p class="para rdfs-comment">
   使用 <a href="http://www.faqs.org/rfcs/rfc1321" class="link external">&raquo;&nbsp;RSA 数据安全公司的 MD5 报文算法</a>计算 <code class="parameter">str</code> 的 MD5 散列值。
  </p>
 </div>


 <div class="refsect1 parameters" id="refsect1-function.md5-parameters">
  <h3 class="title">参数</h3>
  <p class="para">
   <dl>

    
     <dt>
<code class="parameter">str</code></dt>

     <dd>

      <p class="para">
       原始字符串。
      </p>
     </dd>

    
    
     <dt>
<code class="parameter">raw_output</code></dt>

     <dd>

      <p class="para">
       如果可选的 <code class="parameter">raw_output</code> 被设置为 <strong><code>TRUE</code></strong>，那么 MD5 报文摘要将以16字节长度的原始二进制格式返回。
      </p>
     </dd>

    
   </dl>

  </p>
 </div>


 <div class="refsect1 returnvalues" id="refsect1-function.md5-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   以 32 字符十六进制数字形式返回散列值。
  </p>
 </div>


 <div class="refsect1 examples" id="refsect1-function.md5-examples">
  <h3 class="title">范例</h3>
  <p class="para">
   <div class="example" id="example-5921">
    <p><strong>Example #1 <span class="function"><strong>md5()</strong></span> 范例</strong></p>
    <div class="example-contents">
<div class="phpcode"><pre><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br />$str&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">'apple'</span><span style="color: #007700">;<br /><br />if&nbsp;(</span><span style="color: #0000BB">md5</span><span style="color: #007700">(</span><span style="color: #0000BB">$str</span><span style="color: #007700">)&nbsp;===&nbsp;</span><span style="color: #DD0000">'1f3870be274f6c49b3e31a0c6728957f'</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">"Would&nbsp;you&nbsp;like&nbsp;a&nbsp;green&nbsp;or&nbsp;red&nbsp;apple?"</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</pre></div>
    </div>

   </div>
  </p>
 </div>


 <div class="refsect1 seealso" id="refsect1-function.md5-seealso">
  <h3 class="title">参见</h3>
  <p class="para">
   <ul class="simplelist">
    <li class="member"><span class="function"><a href="md5_file.html" class="function" rel="rdfs-seeAlso">md5_file()</a> - 计算指定文件的 MD5 散列值</span></li>
    <li class="member"><span class="function"><a href="sha1_file.html" class="function" rel="rdfs-seeAlso">sha1_file()</a> - 计算文件的 sha1 散列值</span></li>
    <li class="member"><span class="function"><a href="crc32.html" class="function" rel="rdfs-seeAlso">crc32()</a> - 计算一个字符串的 crc32 多项式</span></li>
    <li class="member"><span class="function"><a href="sha1.html" class="function" rel="rdfs-seeAlso">sha1()</a> - 计算字符串的 sha1 散列值</span></li>
    <li class="member"><span class="function"><a href="hash.html" class="function" rel="rdfs-seeAlso">hash()</a> - 生成哈希值 （消息摘要）</span></li>
    <li class="member"><span class="function"><a href="crypt.html" class="function" rel="rdfs-seeAlso">crypt()</a> - 单向字符串散列</span></li>
    <li class="member"><span class="function"><a href="password_hash.html" class="function" rel="rdfs-seeAlso">password_hash()</a> - 创建密码的散列（hash）</span></li>
   </ul>
  </p>
 </div>


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